Temperature sensor and integrated circuit

Abstract

This invention relates to a temperature sensor and an integrated circuit. The temperature sensor includes a current generation module, which comprises both a MOSFET temperature sensing unit and a BJT temperature sensing unit. A PWM generator outputs PWM pulses with different duty cycles to switch between the MOSFET and BJT temperature sensing units, causing them to output currents with temperature coefficient characteristics at different times. Compared to traditional technologies that use only MOSFET or only BJT temperature sensors, this application utilizes a temperature sensor combining MOSFET and BJT temperature sensing units, resulting in high temperature measurement accuracy. This avoids the accuracy deviation caused by packaging stress when using only a BJT temperature sensor, or the error introduced by nonlinear factors when using only a MOSFET temperature sensor, thus achieving accurate temperature measurement.

Description

Technical Field

[0001] This invention relates to the field of temperature control, and in particular to a temperature sensor and integrated circuit. Background Technology

[0002] Temperature sensors have a wide range of applications in industry, transportation, biomechanics, agriculture, and other fields. Analog output IC (Integrated Circuit) temperature sensors are a commonly used type of temperature sensor, offering advantages such as high accuracy, small size, high resolution, and high linearity. CMOS (Complementary Metal Oxide Semiconductor) integrated temperature sensors are also commonly used analog IC temperature sensors. Their main implementation methods include: temperature sensors based on MOS (Metal Oxide Semiconductor) transistors and temperature sensors based on BJT (Bipolar Junction Transistor). MOS transistor-based temperature sensors typically operate in subthreshold mode, containing a nonlinearity factor ζ, resulting in poorer linearity compared to BJT-based temperature sensors. BJT-based temperature sensors, on the other hand, are more susceptible to stress and mismatch. Summary of the Invention

[0003] Therefore, it is necessary to provide a temperature sensor and integrated circuit that addresses the problems of traditional MOSFET-based and BJT-based temperature sensors.

[0004] A temperature sensor, comprising:

[0005] A switching module is used to turn the device on or off under the control of an input PWM pulse signal.

[0006] The current generation module includes a MOSFET temperature sensing unit and a BJT temperature sensing unit. When the switching module is turned on, the MOSFET temperature sensing unit generates a current with temperature coefficient characteristics. When the switching module is turned off, the BJT temperature sensing unit generates a current with temperature coefficient characteristics.

[0007] A mirror current source module, connected to the current generation module, is used to mirror the current with temperature coefficient characteristics and output it.

[0008] In one embodiment, the temperature sensor further includes a PWM generator, which includes a charge / discharge unit and a comparison unit;

[0009] The comparison unit compares the voltage of the charging / discharging unit with a threshold voltage, and outputs a first-level signal when the voltage of the charging / discharging unit is greater than the threshold voltage, and outputs a second-level signal when the voltage of the charging / discharging unit is less than the threshold voltage, thereby forming the PWM pulse signal. In one embodiment, the PWM generator further includes a clock control unit and a switching unit;

[0010] The clock control unit controls the switching unit so that the switching unit controls the charging and discharging unit to switch between charging and discharging states.

[0011] In one embodiment, the switching unit includes a fourth switch and a fifth switch, the fourth switch including a control terminal, a first terminal and a second terminal, and the fifth switch including a control terminal, a first terminal, a second terminal and a third terminal;

[0012] The control terminal of the fourth switch is connected to the output terminal of the clock control unit. The first terminal of the fourth switch is connected to the first terminal of the fifth switch and the first terminal of the charging and discharging unit. The second terminal of the fourth switch is connected to the second terminal of the charging unit. When the clock control unit outputs a first level signal, the fourth switch is closed. When the control unit outputs a second level signal, the fourth switch is turned off.

[0013] The control terminal of the fifth switch is connected to the output terminal of the clock control unit. The second terminal of the fifth switch is grounded, and the third terminal of the fifth switch is connected to an adjustable voltage source. When the clock control unit outputs a first level signal, the first and second terminals of the fifth switch are connected. When the clock control unit outputs a second level signal, the first and third terminals of the fifth switch are connected.

[0014] In one embodiment, the temperature sensor further includes a control module for configuring the magnitude of the adjustable voltage source to adjust the duty cycle of the PWM pulse signal.

[0015] In one embodiment, the MOS transistor temperature sensing unit includes a first MOS transistor, a second MOS transistor, and a third MOS transistor;

[0016] The gates of the first MOSFET, the second MOSFET, and the third MOSFET are connected. The drains of the first MOSFET, the second MOSFET, and the third MOSFET are respectively connected to a preset power supply. The sources of the first MOSFET and the second MOSFET are respectively grounded through the switching module. The source of the third MOSFET is connected to the BJT temperature sensing unit through the switching module.

[0017] When the PWM pulse signal controls the switching module to turn on, the BJT temperature sensing unit is in a short-circuit state, and the first MOSFET, the second MOSFET, and the third MOSFET are in the subthreshold region and generate a current with temperature coefficient characteristics.

[0018] In one embodiment, the BJT temperature sensing unit includes a first transistor and a second transistor, the base and collector of the first transistor and the base and collector of the second transistor are respectively grounded, the emitter of the first transistor is connected to the source of the first MOS transistor, and the emitter of the second transistor is connected to the source of the second MOS transistor and the third MOS transistor through the switching module.

[0019] When the PWM pulse signal controls the switching module to turn off, the first MOSFET and the second MOSFET form a clamping circuit to make the source voltages of the first MOSFET and the second MOSFET the same, and the first transistor and the second transistor generate a current with temperature coefficient characteristics.

[0020] In one embodiment, the switching module includes a first switching branch and a second switching branch;

[0021] The first switch branch is connected in parallel with the BJT temperature sensing unit, and when the first switch branch is turned on, the BJT temperature sensing unit is short-circuited.

[0022] One end of the second switch branch is connected to the third MOS transistor, and the other end is connected to the first switch branch and the BJT temperature sensing unit, respectively.

[0023] In one embodiment, the first switch branch includes a first switch and a second switch, the second switch branch includes a third switch and a resistor, and the first switch, the second switch and the third switch each include a control terminal, a first terminal and a second terminal;

[0024] The control terminals of the first switch, the second switch, and the third switch are respectively connected to the output terminal of the PWM generator;

[0025] The first terminal of the first switch is connected to the common connection point of the source of the first MOSFET and the emitter of the first transistor, and the second terminal of the first switch is connected to the common connection point of the first transistor, the second transistor and ground.

[0026] The first end of the second switch is connected to the common connection point between one end of the resistor and the emitter of the second transistor, and the second end of the second switch is connected to the common connection point between the first transistor, the second transistor and ground;

[0027] The first end of the third switch is connected to the common connection segment between the other end of the resistor and the source of the second MOS transistor, and the second end of the third switch is connected to the source of the third MOS transistor.

[0028] When the PWM generator outputs a first level, it controls the first switch, the second switch, and the third switch to be turned on; when the PWM generator outputs a second level, it controls the first switch, the second switch, and the third switch to be turned off.

[0029] An integrated circuit including the aforementioned temperature sensor.

[0030] In the aforementioned temperature sensor and integrated circuit, the current generation module includes both a MOSFET temperature sensing unit and a BJT temperature sensing unit. The switching module switches between the MOSFET and BJT temperature sensing units to output currents with temperature coefficient characteristics at different times. Compared to traditional technologies that only use MOSFET or BJT temperature sensors, the temperature sensor of this application allows for switching between MOSFET and BJT temperature sensing units as needed. This avoids the accuracy deviation caused by packaging stress when using only BJT temperature sensors, or the error introduced by nonlinear factors when using only MOSFET temperature sensors, thus achieving accurate temperature measurement. Attached Figure Description

[0031] Figure 1 A schematic diagram of a temperature sensor module provided for one embodiment of this application;

[0032] Figure 2 A schematic diagram of a temperature sensor module provided for yet another embodiment of this application;

[0033] Figure 3 A schematic diagram of a temperature sensor circuit structure is provided for one embodiment of this application;

[0034] Figure 4 for Figure 3 The illustrated embodiment provides a schematic diagram of the temperature sensor circuit structure when the switching module is turned on.

[0035] Figure 5 for Figure 3 The illustrated embodiment provides a schematic diagram of the temperature sensor circuit structure when the switching module is off.

[0036] Figure 6 A schematic diagram of a temperature sensor module provided for another embodiment of this application. Detailed Implementation

[0037] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0040] Please see Figure 1 One embodiment of this application provides a temperature sensor, including a switching module 100, a current generation module 200, and a current source mirroring module 300. The switching module 100 can be turned on or off under the control of an input PWM pulse signal. The current generation module 200 is connected to the switching module 100. In this embodiment, the current generation module 200 includes a MOSFET temperature sensing unit 210 and a BJT temperature sensing unit 220. When the switching module 100 is on, the MOSFET temperature sensing unit 210 generates a current with a temperature coefficient characteristic; when the switching module 100 is off, the BJT temperature sensing unit 220 generates a current with a temperature coefficient characteristic. Specifically, the MOSFET temperature sensing unit 210 and the BJT temperature sensing unit 220 can be configured to generate a current with a positive temperature characteristic or a current with a negative temperature coefficient. The current mirroring module 300 is connected to the current generation module 200 and is used to mirror the current with temperature coefficient characteristics, so that an external device connected to the temperature sensor can calculate the current ambient temperature based on the current with temperature coefficient characteristics.

[0041] In the temperature sensor provided in the above embodiments, the current generation module 200 includes both a MOSFET temperature sensing unit 210 and a BJT temperature sensing unit 220. The switching module 100 switches the MOSFET temperature sensing unit 210 and the BJT temperature sensing unit 220 so that they output currents with temperature coefficient characteristics at different times. Compared with the traditional technology that only uses a MOSFET temperature sensor or only uses a BJT temperature sensor, the temperature sensor of this application can switch the MOSFET temperature sensing unit 210 and the BJT temperature sensing unit 220 at any time as needed. This avoids the accuracy deviation caused by the packaging stress when only using a BJT temperature sensor, or the error introduced by the nonlinear factor when only using a MOSFET temperature sensor, thereby achieving accurate temperature measurement.

[0042] In one embodiment, such as Figure 2 As shown, the temperature sensor also includes a PWM generator 400, which is connected to the switching module 100 and used to generate PWM pulse signals to control the switching module 100 to turn on and off. The PWM generator 400 includes a charging / discharging unit 410 and a comparison unit 420. The comparison unit 420 compares the voltage of the charging / discharging unit 410 with a threshold voltage. When the voltage of the charging / discharging unit 410 is greater than or equal to the threshold voltage, it outputs a first-level signal; when the voltage of the charging / discharging unit 410 is less than the threshold voltage, it outputs a second-level signal to form a PWM pulse signal. Figure 3 Taking the circuit shown as an example, the charging / discharging unit 410 can be implemented using a capacitor C, and the comparison unit 420 can be implemented using an operational amplifier A. Operational amplifier A includes a first input terminal, a second input terminal, and an output terminal. The first input terminal is connected to the second terminal of capacitor C and is used to input the capacitor voltage Vc. The second input terminal is used to input the threshold voltage V. threh The first input terminal is the non-inverting input terminal, and the second input terminal is the inverting input terminal. When the capacitor voltage Vc is greater than the threshold voltage Vthrehold, the operational amplifier A outputs a high-level signal, and when the capacitor voltage Vc is greater than the threshold voltage Vthrehold, the operational amplifier A outputs a low-level signal. The PWM pulse signal is composed of alternating high-level and low-level signals.

[0043] Furthermore, the PWM generator 400 also includes a clock control unit 430 and a switching unit 440. The switching unit 440 is connected to the charging and discharging unit 410, and the clock control unit 430 can control the switching unit 440 so that the switching unit 440 controls the charging and discharging unit 410 to switch between charging and discharging states.

[0044] Specifically, such as Figure 3As shown, the switching unit 440 includes a fourth switch S4 and a fifth switch S5. Both the fourth switch S4 and the fifth switch S5 are controlled by the clock control unit 430. The fourth switch S4 includes a control terminal, a first terminal, and a second terminal. The control terminal of the fourth switch S4 is connected to the output terminal of the clock control unit 430. The first terminal of the fourth switch S4 is connected to the first terminal of the fifth switch S5 and the first terminal of the charging / discharging unit 410. The second terminal of the fourth switch S4 is connected to the second terminal of the charging / discharging unit 410 and the first input terminal of the operational amplifier A. In this embodiment, the clock signal generated by the clock control unit 430 controls the fourth switch S4 to close or close. When the clock control unit 430 outputs a first-level signal, the fourth switch S4 closes; when the clock control unit 430 outputs a second-level signal, the fourth switch S4 closes. In some alternative embodiments, an external clock source can be used instead of the clock control unit 430.

[0045] The fifth switch S5 includes a control terminal, a first terminal, a second terminal, and a third terminal. The control terminal of the fifth switch S5 is connected to the output terminal of the clock control unit 430. The first terminal of the fifth switch S5 is connected to the common connection point of the first terminal of the fourth switch S4 and the first terminal of capacitor C. The second terminal of the fifth switch S5 is grounded. The third terminal of the fifth switch S5 is connected to a preset adjustable voltage source. When the clock control unit 430 outputs a first-level signal, the first and second terminals of the fifth switch S5 are connected, meaning that capacitor C is grounded through the fifth switch S5. At this time, the charge accumulated on capacitor C will be discharged through the fifth switch S5, i.e., controlling capacitor C to discharge. When the clock control unit 430 outputs a second-level signal, the first and third terminals of the fifth switch S5 are connected, meaning that the output voltage Vadj of the adjustable voltage source charges capacitor C through the fifth switch S5. Optionally, the adjustable voltage source can be a voltage source built into the temperature sensor, or it can be implemented using an external voltage source.

[0046] Optionally, the first level signal of the clock control unit 430 is a high level signal and the second level signal is a low level signal; or, the first level signal of the clock control unit 430 is a low level signal and the second level signal is a high level signal.

[0047] In one specific embodiment, with Figure 3Taking the circuit shown as an example, when the clock control unit 430 outputs a first-level signal, the fourth switch S4 is closed, and the first and second terminals of the fifth switch S5 are connected, meaning capacitor C is short-circuited. Furthermore, the fifth switch S5 is connected to ground, and capacitor C is in a discharging state. At this time, the PWM generator 400 is in a reset state. When the clock control unit 430 outputs a second-level signal, the fourth switch S4 is turned off, and the first and third terminals of the fifth switch S5 are connected. This means the adjustable voltage source charges capacitor C through switch S5. During charging, when the voltage of capacitor C is greater than or equal to the threshold voltage, operational amplifier A outputs a high-level signal; when the voltage of capacitor C is less than the threshold voltage, operational amplifier A outputs a low-level signal. The alternating high and low level signals form a PWM pulse signal. Furthermore, the duty cycle of the PWM pulse signal can be adjusted by regulating the magnitude of the adjustable voltage source.

[0048] The PWM pulse signal generated by the PWM generator 400 is used to control the operation of the MOSFET temperature sensing unit 210 and the BJT temperature sensing unit 220. Please continue reading. Figure 3 In one embodiment, the MOSFET temperature sensing unit 210 includes a first MOSFET M1, a second MOSFET M2, and a third MOSFET M3. The first MOSFET M1, the second MOSFET M2, and the third MOSFET M3 can all be N-type transistors or all be P-type transistors. The gates of the first MOSFET M1, the second MOSFET M2, and the third MOSFET M3 are connected together. The drains of the first MOSFET M1, the second MOSFET M2, and the third MOSFET M3 are respectively connected to a preset power supply VDD through a current mirror module 300. The preset power supply VDD provides the operating voltage for the current mirror source and can be built into the temperature sensor or implemented through an external power supply. The current mirror module 300 includes a first current mirror source 310, a second current mirror source 320, and a third current mirror source 330, which are respectively connected to the preset power supply VDD. The drain of the first MOSFET is connected to the first current mirror 310, and the drains of the second MOSFET M2 and the third MOSFET M3 are connected to the second current mirror 320, respectively. The sources of the first MOSFET M1 and the second MOSFET M2 are grounded through the switching module 100, and the source of the third MOSFET M3 is connected to the BJT temperature sensing unit 220 through the switching module 100.

[0049] Furthermore, the BJT temperature sensing unit 220 includes a first transistor Q1 and a second transistor Q2. The base and collector of the first transistor Q1 and the base and collector of the second transistor Q2 are respectively grounded. The emitter of the first transistor Q1 is connected to the source of the first MOSFET M1, and the emitter of the second transistor Q2 is connected to the source of the second MOSFET M2 and the third MOSFET M3 through the switching module 100.

[0050] Furthermore, the switch module 100 includes a first switch branch and a second switch branch. The first switch branch is connected in parallel with the BJT temperature sensing unit 230. When the first switch branch is on, the BJT temperature sensing unit 230 is short-circuited. One end of the second switch branch is connected to the third MOSFET M3, and the other end is connected to both the first switch branch and the BJT temperature sensing unit 220. When the second switch branch is off, the third MOSFET M3 is turned off. Specifically, the first switch branch includes a first switch S1 and a second switch S2, and the second switch branch includes a third switch S3 and a resistor R1. The first switch S1, the second switch S2, and the third switch S3 each include a control terminal, a first terminal, and a second terminal. The control terminals of the first switch S1, the second switch S2, and the third switch S3 are respectively connected to the output terminals of the PWM generator 400. The first terminal of the first switch S1 is connected to the common connection point of the source of the first MOSFET M1 and the emitter of the first transistor Q1, and the second terminal of the first switch S1 is connected to the common connection point of the first transistor Q1, the second transistor Q2, and ground. The first terminal of the second switch S2 is connected to one end of resistor R1 and the common connection point of the emitter of the second transistor Q2. The second terminal of the second switch S2 is connected to the common connection point of the first transistor Q1, the second transistor Q2, and ground. The first terminal of the third switch S3 is connected to the common connection point of the other end of resistor R1 and the source of the second MOSFET. The second terminal of the third switch S3 is connected to the source of the third MOSFET M3. The PWM pulse signal output by the PWM generator 400 can control the conduction and cutoff of the first switch S1, the second switch S2, and the third switch S3. When the PWM generator 400 outputs a first level, it controls the first switch S1, the second switch S2, and the third switch S3 to conduct; when the PWM generator 400 outputs a second level, it controls the first switch S1, the second switch S2, and the third switch S3 to cut off. The first level can be high and the second level low, or the first level can be low and the second level high.

[0051] When the PWM pulse signal controls the first and second switching branches to turn on, the BJT temperature sensing unit 220 is in a short-circuit state. The first MOSFET M1, the second MOSFET M2, and the third MOSFET M3 are in the subthreshold region and generate a current with temperature coefficient characteristics. When the PWM pulse signal controls the first and second switching branches to turn off, the first MOSFET M1 and the second MOSFET M2 form a clamping circuit, and the third MOSFET M3 is disconnected from the circuit, so that the source voltages of the first MOSFET M1 and the second MOSFET M2 are the same, and the first transistor Q1 and the second transistor Q2 generate a current with temperature coefficient characteristics.

[0052] Specifically, when the PWM pulse signal controls the first switch S1, the second switch S2, and the third switch S3 to be turned on, the equivalent circuit of the temperature sensor is as follows: Figure 4 As shown, the BJT temperature sensing unit 220 is short-circuited by the switching module 100. The source of the first MOSFET M1 is grounded through the first switch S1, and the sources of the second MOSFET M2 and the third MOSFET M3 are grounded through resistor R1 and switch S2, respectively. At this time, the current with temperature coefficient characteristics is provided by the first MOSFET M1, the second MOSFET M2, and the third MOSFET M3 operating in the subthreshold region. Assume the current with temperature coefficient is I. ptat The expression for the current is as follows:

[0053] I ptat =(V GS1 -V GS2 ) / R (1)

[0054] Where V GS1 V is the gate-source voltage difference of the first MOSFET M1. GS2 This is the gate-source voltage difference of the second MOSFET M2.

[0055] Since the current of a MOSFET operating in the subthreshold region is:

[0056]

[0057] in, That is, the width-to-length ratio of the MOSFET, μ represents the carrier mobility, and ε si φ represents the dielectric constant of silicon, a semiconductor material. S φ represents the surface potential of a MOSFET. B N represents the substrate Fermi potential of the MOSFET. ch This indicates the substrate doping concentration of the MOSFET. This represents the thermoelectric potential of the MOSFET, where k is the Boltzmann constant, T is the thermodynamic temperature (i.e., absolute temperature), and q is the electron charge (1.6 × 10⁻⁶). –19 C).

[0058] And because

[0059] Combining equations (2) and (3), we can obtain:

[0060]

[0061] The calculation yielded:

[0062] therefore:

[0063] Assume n(T)≈n(T0),

[0064] We can obtain:

[0065] Among them, K G =K T +V gs (T0)-V th (T0)-V off .

[0066] In the above formula, T represents the current actual temperature, T0 represents the reference temperature, and V off This represents the correction constant term. Since K G It is usually a negative value, therefore, it can be seen from equation (7) that V gs It decreases with increasing temperature, meaning it has a negative temperature coefficient, so ΔV gs It has a positive temperature coefficient. Therefore, I PTAT_MOS The current is:

[0067]

[0068] In other words, the MOSFET temperature sensing unit can generate a current with a positive temperature coefficient.

[0069] When the PWM pulse signal controls the first switch S1, the second switch S2, and the third switch S3 to turn off, the equivalent circuit is as follows: Figure 5 As shown, the third MOSFET M3 is open-circuited, and the first MOSFET M1 and the second MOSFET M2 form a clamping circuit, thus making the source voltages of the first MOSFET M1 and the second MOSFET M2 equal. At this time, the current with temperature coefficient characteristics is generated by the first transistor Q1 and the second transistor Q2. The current expression is as follows:

[0070] I = (V) BE1 -V BE2 ) / R (8)

[0071] Among them, V BE1 This represents the voltage difference between the base and emitter of the first transistor Q1, V. BE2This represents the voltage difference between the base and emitter of the second transistor Q2, and R is the resistance value of resistor R1.

[0072] For bipolar devices, the collector current is:

[0073] I C =I S exp(V BE / V T (9)

[0074] Among them, I s This represents the saturation current of a BJT transistor, V. BE This represents the voltage difference between the base and emitter of a BJT transistor. The value represents the thermoelectric potential of the BJT transistor, k is the Boltzmann constant, T is the thermodynamic temperature (i.e., absolute temperature), and q is the electron charge (1.6 × 10⁻⁶). –19 C).

[0075] We can obtain:

[0076] because Therefore, V BE It has negative temperature characteristics, and therefore ΔV BE If it has a positive temperature characteristic, then the current expression is:

[0077]

[0078] In other words, the BJT temperature sensing unit can generate a current with a positive temperature coefficient.

[0079] As shown in the above formula, when the PWM pulse signal controls the switching module 100 to be turned on, the MOSFET temperature sensing unit 210 generates a current with a positive temperature coefficient; when the PWM pulse signal controls the switching module 100 to be turned off, the BJT temperature sensing unit 220 generates a current with a positive temperature coefficient. The current mirror current source module 300 is connected to the current generation module and is used to mirror the current with a positive temperature coefficient for output. The above temperature sensor controls the on and off of the switching module 100 by generating a PWM pulse signal with adjustable pulse width, and switches between the MOSFET temperature sensing unit 210 and the BJT temperature sensing unit 220 as needed to generate a current with a positive temperature coefficient. This avoids the accuracy deviation caused by the packaging stress when using only a BJT temperature sensor, or the error introduced by the nonlinear factor when using only a MOSFET temperature sensor, thereby achieving accurate temperature measurement.

[0080] For further details, please refer to Figure 6In one embodiment, the temperature sensor further includes a current detection circuit 500 connected to the mirror current source module 300. Specifically, the current detection circuit 500 is connected to the third mirror current source 330 to sample current with temperature coefficient characteristics and determine the temperature corresponding to the current based on the temperature coefficient characteristics of the current. For example... Figure 3 The current detection circuit 500 can be an ADC (Analog-to-digital converter). Alternatively, the current detection circuit 500 can be an analog front-end (AFE) circuit or other circuits with signal acquisition and processing functions.

[0081] In the temperature sensor provided in the above embodiment, the current generation module 200 includes both a MOSFET temperature sensing unit 210 and a BJT temperature sensing unit 220. The PWM generator 400 outputs PWM pulses with different duty cycles to switch the MOSFET temperature sensing unit 210 and the BJT temperature sensing unit 220 so that they output currents with temperature coefficient characteristics at different times. Compared with the traditional technology that only uses MOSFET temperature sensors or only uses BJT temperature sensors, the temperature sensor of this application that uses a combination of MOSFET temperature sensing unit 210 and BJT temperature sensing unit 220 has high temperature measurement accuracy. It avoids the accuracy deviation caused by the packaging stress when only using BJT temperature sensors, or the error introduced by nonlinear factors when only using MOSFET temperature sensors, and achieves accurate temperature measurement.

[0082] This application also provides an integrated circuit including the aforementioned temperature sensor. Optionally, the temperature sensor can be integrated into an MCU, or into a SOC (System On a Chip) or SIP (System In a Package).

[0083] The integrated circuit of this application includes both a MOSFET temperature sensing unit and a BJT temperature sensing unit as its temperature sensor. A PWM generator produces PWM pulse signals to control the switching module's turn-off. This switching module then switches the MOSFET and BJT temperature sensing units to output currents with temperature coefficient characteristics at different times. The integrated circuit can calculate the current's temperature based on this temperature coefficient characteristic, avoiding the accuracy deviation caused by packaging stress when using only a BJT temperature sensor, or the error introduced by nonlinear factors when using only a MOSFET temperature sensor, thus achieving accurate temperature measurement.

[0084] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A temperature sensor, characterized by, include: A switching module is used to turn the device on or off under the control of an input PWM pulse signal. The current generation module includes a MOSFET temperature sensing unit and a BJT temperature sensing unit. When the switching module is turned on, the MOSFET temperature sensing unit generates a current with temperature coefficient characteristics, and the BJT temperature sensing unit is in a short-circuit state. When the switching module is turned off, the MOSFET temperature sensing unit forms a clamping circuit, and the BJT temperature sensing unit generates a current with temperature coefficient characteristics. A mirror current source module, connected to the current generation module, is used to mirror the current with temperature coefficient characteristics and output it.

2. The temperature sensor of claim 1, wherein, The temperature sensor also includes a PWM generator. The PWM generator includes a charge / discharge unit and a comparison unit; The comparison unit is used to compare the voltage of the charging and discharging unit with the threshold voltage, and outputs a first level signal when the voltage of the charging and discharging unit is greater than the threshold voltage, and outputs a second level signal when the voltage of the charging and discharging unit is less than the threshold voltage, so as to form the PWM pulse signal.

3. The temperature sensor of claim 2, wherein, The PWM generator also includes a clock control unit and a switching unit; The clock control unit controls the switching unit so that the switching unit controls the charging and discharging unit to switch between charging and discharging states.

4. The temperature sensor of claim 3, wherein, The switching unit includes a fourth switch and a fifth switch. The fourth switch includes a control terminal, a first terminal, and a second terminal. The fifth switch includes a control terminal, a first terminal, a second terminal, and a third terminal. The control terminal of the fourth switch is connected to the output terminal of the clock control unit. The first terminal of the fourth switch is connected to the first terminal of the fifth switch and the first terminal of the charging and discharging unit. The second terminal of the fourth switch is connected to the second terminal of the charging and discharging unit. When the clock control unit outputs a first level signal, the fourth switch is closed. When the control unit outputs a second level signal, the fourth switch is turned off. The control terminal of the fifth switch is connected to the output terminal of the clock control unit. The second terminal of the fifth switch is grounded, and the third terminal of the fifth switch is connected to a preset adjustable voltage source. When the clock control unit outputs a first level signal, the first and second terminals of the fifth switch are connected. When the clock control unit outputs a second level signal, the first and third terminals of the fifth switch are connected.

5. The temperature sensor of claim 4, wherein, The temperature sensor also includes a control module, which is used to configure the output voltage of the adjustable voltage source to adjust the duty cycle of the PWM pulse signal.

6. The temperature sensor of claim 5, wherein, The MOSFET temperature sensing unit includes a first MOSFET, a second MOSFET, and a third MOSFET; The gates of the first MOSFET, the second MOSFET, and the third MOSFET are connected. The drains of the first MOSFET, the second MOSFET, and the third MOSFET are respectively connected to a preset power supply. The sources of the first MOSFET and the second MOSFET are respectively grounded through the switching module. The source of the third MOSFET is connected to the BJT temperature sensing unit through the switching module. When the PWM pulse signal controls the switching module to turn on, the BJT temperature sensing unit is in a short-circuit state, and the first MOSFET, the second MOSFET, and the third MOSFET are in the subthreshold region and generate a current with temperature coefficient characteristics.

7. The temperature sensor according to claim 6, characterized in that, The BJT temperature sensing unit includes a first transistor and a second transistor. The base and collector of the first transistor and the base and collector of the second transistor are respectively grounded. The emitter of the first transistor is connected to the source of the first MOS transistor. The emitter of the second transistor is connected to the source of the second MOS transistor and the third MOS transistor through the switching module. When the PWM pulse signal controls the switching module to turn off, the first MOSFET and the second MOSFET form a clamping circuit to make the source voltages of the first MOSFET and the second MOSFET the same, and the first transistor and the second transistor generate a current with temperature coefficient characteristics.

8. The temperature sensor according to claim 7, characterized in that, The switch module includes a first switch branch and a second switch branch; The first switch branch is connected in parallel with the BJT temperature sensing unit, and when the first switch branch is turned on, the BJT temperature sensing unit is short-circuited. One end of the second switch branch is connected to the third MOS transistor, and the other end is connected to the first switch branch and the BJT temperature sensing unit, respectively.

9. The temperature sensor according to claim 8, characterized in that, The first switch branch includes a first switch and a second switch, and the second switch branch includes a third switch and a resistor. The first switch, the second switch and the third switch each include a control terminal, a first terminal and a second terminal. The control terminals of the first switch, the second switch, and the third switch are respectively connected to the output terminal of the PWM generator; The first terminal of the first switch is connected to the common connection point of the source of the first MOSFET and the emitter of the first transistor, and the second terminal of the first switch is connected to the common connection point of the first transistor, the second transistor and ground. The first end of the second switch is connected to the common connection point between one end of the resistor and the emitter of the second transistor, and the second end of the second switch is connected to the common connection point between the first transistor, the second transistor and ground; The first end of the third switch is connected to the common connection point between the other end of the resistor and the source of the second MOS transistor, and the second end of the third switch is connected to the source of the third MOS transistor. When the PWM generator outputs a first level, it controls the first switch, the second switch, and the third switch to be turned on; when the PWM generator outputs a second level, it controls the first switch, the second switch, and the third switch to be turned off.

10. An integrated circuit, characterized in that, The integrated circuit includes a temperature sensor as described in any one of claims 1-9.

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